Inspection apparatus for sheet

Abstract

An inspection apparatus for a sheet includes: white LED illuminators which irradiate a sheet of paper with light containing visible light: IR-LED illuminators which irradiate the sheet of paper with light containing infrared rays: two visible color cameras; one IR monochrome camera: an IR filter which eliminates the visible light in the light emitted from the white LED illuminators and the IR-LED illuminators and reflected off the sheet of paper, and makes only the infrared rays incident on the IR monochrome camera; and a control device which determines appropriateness of a pattern portion on the sheet of paper on the basis of the visible light made incident on the visible color cameras, and determines appropriateness of pattern portions on the sheet of paper on the basis of the infrared rays made incident on the IR monochrome camera.

The invention claimed is: 
     
       1. An inspection apparatus for a sheet including a pattern portion printed with an ordinary ink and a pattern portion printed with an ink containing an infrared component, comprising:
 a white light source configured to irradiate the sheet with light containing visible light; 
 an infrared light source configured to irradiate the sheet with light containing infrared rays; 
 two visible light imaging means for imaging the sheet; 
 one infrared imaging means for imaging the sheet, the infrared imaging means being located in a position which is out of fields of view of the two visible light imaging means; 
 an infrared filter configured to eliminate the visible light in the light emitted from the white light source and the infrared light source and reflected off the sheet, and to make only the infrared rays incident on the infrared imaging means; and 
 a control device configured to determine appropriateness of the pattern portion printed with the ordinary ink on the sheet on the basis of the visible light emitted from the white light source and the infrared light source, reflected off the sheet, and made incident on the two visible light imaging means, and to determine appropriateness of the pattern portion printed with the ink containing the infrared component on the sheet on the basis of the infrared rays emitted from the white light source and the infrared light source, reflected off the sheet, and made incident on the one infrared imaging means. 
 
     
     
       2. The inspection apparatus for a sheet according to  claim 1 , wherein the infrared imaging means is installed between the two visible light imaging means disposed away from each other in a sheet width direction. 
     
     
       3. The inspection apparatus for a sheet according to  claim 1 , wherein the two visible light imaging means and the infrared imaging means are disposed in positions equidistant from an imaging plane of the sheet.